Scaling device

ABSTRACT

A device ( 1 ) for the scaled depositing of bags ( 6, 6   a ) arriving immediately behind each other from a bag production machine ( 12 ), the device comprising a conveyor belt ( 2 ) and a pressing belt ( 3 ) extending at least partially parallel at a distance to the conveyor belt ( 2 ), characterized by at least one beater arm ( 4 ) directly in front of the conveyor belt ( 2 ), wherein a force can be applied to the end of each bag ( 6 ) by means of the beater arm ( 4 ), the force pressing the end of the bag ( 6 ) beneath the level of the conveyor surface of the conveyor belt ( 2 ).

The present invention concerns an apparatus for the overlapped deposition of bags arriving immediately after each other from a bag-making machine.

Bag-making machines are known that create a continuous strip of bags, in particular plastic bags. For the manufacture of package quantities that are conventionally used in households, a certain number of bags is wound up into a roll. One possibility is to perforate the strip transversely between succeeding bags and to roll up the desired length all together. Alternatively, the individual bags are separated and overlapped, i.e. rolled up like roof shingles with a certain amount of overlap. To this end it is necessary that the individual bags be set down overlapped.

An apparatus for the overlapped deposition of bags arriving immediately after each other is known from the German patent application 25 34 298 [U.S. Pat. No. 4,000,864]. In this publication, a conveyor belt is described that grips the bags and deposits them on a strip or belt conveyor. The speed of the upstream conveyor belt varies sinusoidally. The bags are picked up by the conveyor belt at maximum speed and are dropped off at minimum speed so that an overlap of the bags is created on the track or belt conveyor.

The disadvantage of this known solution from the prior art is the expensive construction of the transfer conveyor belt and controlling it at variable speeds. For this reason, it is the object of the present invention to provide a new apparatus for the overlapped deposition of bags arriving immediately after each other that does not have the disadvantages mentioned above.

This object is attained by an apparatus with the characteristics of claim 1. Advantageous embodiments can be learned from the dependent claims.

The apparatus in accordance with the invention has a conveyor belt and a pressing belt that runs at least in part parallel to the conveyor belt at a small spacing. In addition, the apparatus has immediately upstream of the conveyor belt at least one deflecting arm that exerts a force on the end of each bag to push the end of the bag beneath the level of the conveyor surface of the conveyor belt. The pressing down of the end of the bag by the deflecting arm ensures that the end of the bag engages the downstream conveyor belt and the leading end of the following bag slides reliably over the trailing end of the preceding bag.

Preferably, the transport speed of the conveyor belt corresponds to the speed of the pressing belt. But this transport speed is less than the feed speed at which the bags leave the bag-making machine. The larger the difference between the speeds of the conveyor belt and the feed speed, the larger is the overlap between two immediately succeeding bags.

The spacing between the conveyor belt and the pressing belt is selected in such a way that a bag lying on the transport belt in the region where the pressing belt runs parallel to the conveyor belt is pinched between the conveyor belt and the pressing belt and thus is fixed. This prevents the bag from sliding off the conveyor belt when the deflecting arm exerts a force on the trailing end of the bag.

In a preferred embodiment of the invention, a roller is mounted on the side of the deflecting arm that engages the end of the bag. When the deflecting arm engages the bag, the roller rolls on the bag material. As a result, friction between the deflecting arm and the bag is decreased and the danger of damaging the bag is reduced.

In a further advantageous embodiment, the deflecting arm is pivoted at one end and its pivot axis is parallel to the transport direction of the bags. The deflecting arm thus rotates in a plane perpendicular to the transport direction.

As a result of this configuration, the deflecting arm engages the bag parallel to the edge at the end of the bag. As a result of pivoting around one end of the deflecting arm, pivoting of the deflecting arm at a constant angular frequency is possible dependent on and in relation to the feed speed of the bags. Optionally, two or more deflecting arms are connected rotatable with each other around a joint pivot axis. Preferably, the pivot axis of the deflecting arm is level with the bag. As a result, the entire contact surface of the deflecting arm simultaneously engages at the end of the bag.

Preferably, the apparatus has two deflecting arms that rotate synchronously in opposite directions. Thus a deflecting arm is mounted on each side of the sting of bags. The rotation of the deflecting arms is synchronized in such a way that both deflecting arms simultaneously engage the trailing end of the bag.

In one embodiment of the invention, the apparatus has a pinch roller of the pressing belt between the conveyor belt and the pressing belt for creating a flared intake mouth. The leading end of the next bag that arrives on the conveyor belt is guided into the flared intake mouth. The pinch roller and the part of the pressing belt confronting the pinch roller fix the bags on the conveyor belt. This way, the position of the pinch roller of the pressing belt is preferably variable. In the process, the depth of the flared intake mouth and the position on the conveyor belt starting at that point at which a bag is fixed is variable. The position of the pinch roller is, for example, selectable dependent on the format of the belt.

In a further embodiment of the invention, the conveyor surface of the conveyor belt is inclined downward at least partially with respect to the horizontal in the transport direction, and the pivot axis of the deflecting arm is above the end of the conveyor belt facing the deflecting arm. As a result of this the leading end of the arriving bag on the conveyor belt lies down. If the pinch roller and the pressing belt form a flared intake mouth together with the transporting conveyor belt, the leading end of the arriving bag then enters the flared intake mouth Optionally, the invention has a suction apparatus under the conveyor belt. This way, the bag lies flat on the conveyor belt.

Further, optionally, the apparatus has a cross cutter that is mounted in the transport direction of the bags upstream of the deflecting arm. By means of the cross cutter, arriving bags are separated from each other in the form of a continuous strip.

The present invention shall be explained in further detail by with reference to an embodiment. Therein:

FIG. 1 is a side view of an overlapping apparatus in accordance with the invention; and

FIG. 2 shows two synchronously rotatable deflecting arms above a bag.

FIG. 1 is a side view of an apparatus 1 for the overlapped deposition of bags 6. The apparatus 1 is provided with a conveyor belt 2, a pressing belt 3, two deflecting arms 4, a pinch roller 5, a pattern sensor 7, pull rollers 8, a cross cutter 9 and feed belts 10. The pinch roller 5 presses the pressing belt 3 against the conveyor belt 2. The bags 6, coming from a feed belts are transported to the conveyor belt 2, where they are deposited overlapped. Upstream in the transport direction of the pinch roller 5, the conveyor belt 2 and pressing belt 3 form a tapered intake. Starting at the pinch roller 5, the conveyor belt 2 and the pressing belt 3 run parallel to each other at a small spacing in some regions.

The two deflecting arms 4 are mounted directly upstream in the transport direction of the bags 6 from the conveyor belt 2. Upstream of the deflecting arms 4 in the transport direction of the bags 6, are the pattern sensor 7, the pull rollers 8, the cross cutter 9 and the feeder belts 10. The part of the conveyor belt 2 that forms the flared intake mouth, as well as its part that runs parallel to the pressing belt 3 are inclined downward in the transport direction of the bags 6, with respect to the horizontal H, which essentially corresponds to a shop floor. The rotation axes of the deflecting arms 4 are above the end of the conveyor belt 2 that is facing the deflecting arms 4.

A bag-making machine 12 creates a continuous strip 6 a of bags that is fed into the overlapping apparatus 1. The pattern sensor 7 recognizes the end of each bag 6 in the strip 6 a of bags and transmits a corresponding output for controlling the draw rollers 8 to an unillustrated electronic controller. The cross cutter 9 divides the continuous strip 6 a of bags into individual bags 6. The bags 6 are transported further by the feeder belts 10.

The leading end of each bag 6 bends down while being transported further as a result of the weight of the bag 6 and moves into the flared intake mouth. This way, the bag 6 is gripped between the conveyor belt 2 and the pressing belt 3. The position of the pinch roller 5 is variable, as indicated in FIG. 1 by the double arrow. As a result, the overlapping apparatus 1 can be adapted to various bag sizes, that is bag widths or bag lengths.

The deflecting arms 4 engage the end of each bag 6 and thereby exert a force that pushes the end of the bag below the level of the transport surface of the belt 2. This ensures that the bag end engages the conveyor belt 2 and the leading end of the following bag comes to rest above the trailing end of the preceding bag.

FIG. 2 shows the two deflecting arms 4 in detail. Each deflecting arm 4 is pivotal at one of its ends around a pivot axis 4 a. The pivot axes 4 a of the two deflecting arms are located on different sides of the bag 6. The transport direction of the bags in FIG. 2 is perpendicular to the plane of the drawing. The pivot axes 4 a of the deflecting arms 4 are located level with the bag 6 left and right of the bag. The two deflecting arms 4 rotate, as indicated by arrows in FIG. 2, in opposite directions and are synchronized in such a way that they simultaneously engage the end of the bag 6. The surface of each deflecting arm 4 that engaged the bag 6 is formed by a roller 4 b whose rotation axis extends through the pivot axis 4 a of the respective deflecting arm 4.

The travel speed of the belt 2 corresponds to the speed of the pressing belt 3 and is less than the speed at which the strip 6 a of bags reaches the apparatus 1 and the feed belts 10 further transport the separated bags 6. As a result of the relationship of the travel speed of the belt 2 and the feed speed of the bags 6, the degree of overlap of the bags 6 can be determined on the belt 2. Subsequently, the bags 6 that have been deposited by the apparatus 1 like roof shingles above each other, are fed to a roll-forming apparatus 11.

Of course, the strip 6 a of bags can, instead of coming from the bag-making machine 12, also be made supplied by any other feeding unit. 

1. An apparatus for the overlapped deposition of bags arriving immediately one after another from a bag-making machine, the apparatus being provided with a conveyor belt and with a pressing belt that runs at least in part parallel to the conveyor belt at a small spacing, characterized in, that wherein at least one deflecting arm immediately upstream of the conveyor belt can exert a force on the end of each bag to push the end of the bag below the level of the transport surface of the conveyor belt.
 2. The apparatus according to claim 1 wherein the surface of the deflecting arm that engages the end of the bag is formed by a roller.
 3. The apparatus according to claim 1 wherein the deflecting arm is pivoted at one end and the pivot axis is parallel to the transport direction of the bags.
 4. The apparatus according to claim 3, further comprising two deflecting arms that can be rotated synchronously in the opposite direction.
 5. The apparatus according to one of claims 1 further comprising a pinch roller for creating a flared intake mouth between conveyor belt and pressing belt.
 6. The apparatus according to claim 5 wherein the position of the pinch roller of the pressing belt is variable in the transport direction.
 7. The apparatus according to claim 1 wherein the conveying surface of the conveyor belt is inclined downward with respect to the horizontal at least in part in the transport direction, and the pivot axis of the deflecting arm is above the end of the conveyor belt adjacent the deflecting arm.
 8. The apparatus according to claim 1 further comprising a suction apparatus under the conveyor belt.
 9. The apparatus according to claim 1 wherein the speed of the conveyor belt corresponds to the speed of the pressing belt and is lower than a feed speed of the bags.
 10. The apparatus according to claim 1 further comprising a cross cutter mounted in the transport direction of the bags upstream of the deflecting arm.
 11. An apparatus for converting a stream of end-to-end flat flexible objects arriving in a transport direction at a feed speed into a stream of overlapped objects, the apparatus comprising: a transport belt; a pressing belt closely juxtaposed with the transport belt and defining therewith an intake mouth open upstream in the direction, the stream of end-to-end flat flexible objects being fed in the direction into the mouth; means for driving the belts at a transport speed substantially slower than the feed speed, whereby the objects are slowed when they engage between the belts; a deflecting arm upstream of the lower transport belt and pivotal about an axis generally parallel to the transport direction; and means for pivoting the arm into engagement with one end of each of the objects to displace the engaged ends transversely out of alignment in the direction with an immediately adjacent end of a preceding or following object, whereby the objects overlap between the belts.
 12. The apparatus defined in claim 11 wherein the means for pivoting engages the arm against the trailing end of each of the objects to displace it downward and transversely to the transport direction.
 13. The apparatus defined in claim 11 wherein one of the belts is provided with a pinch roller pressing the one belt against the other belt, the other belt extending generally parallel to the transport direction upstream from the pinch roller, the one belt extending at an acute angle to the transport direction away from the other belt upstream of the pinch roller.
 14. The apparatus defined in claim 13 wherein the one belt is generally above the other belt.
 15. The apparatus defined in claim 11 wherein there are two of the arms each pivotal about a respective axis, the axes flanking the stream of objects.
 16. An apparatus for converting a stream of end-to-end flat flexible objects arriving in a transport direction at a feed speed into a stream of overlapped objects, the apparatus comprising: a lower transport belt; an upper pressing belt closely juxtaposed with the transport belt; a pinch roller pressing one of the belts belt against the other belt, the other belt extending generally parallel to the transport direction upstream from the pinch roller, the one belt extending at an acute angle to the transport direction away from the other belt upstream of the pinch roller and defining therewith an intake mouth open upstream in the direction, the stream of end-to-end flat flexible objects being fed in the direction into the mouth, the belts pinching the objects downstream of the pinch roller; means for driving the belts at a transport speed substantially slower than the feed speed, whereby the objects are slowed when they are pinched between the belts; a deflecting arm upstream of the lower transport belt and pivotal about an axis generally parallel to the transport direction; and means for pivoting the arm into engagement with a trailing end of each of the objects to displace the trailing ends transversely downward out of alignment in the direction with an immediately adjacent end of a following one of the objects, whereby the objects overlap between the belts. 